Given the group interaction parameters between various groups, how to use UNIFAC to determine the composition
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Substances A and B are partially miscible with each other, resulting in two liquid phases. Given the interaction parameters between various constituent groups, how can Aspen Plus be used to determine the equilibrium compositions of the two phases at different temperatures?
A bit confused. Are you getting the interaction parameter between the AB components, or the interaction parameters among the various functional groups within each of the AB components? If it is the former, the parameters required to convert it into the corresponding thermodynamic model used within ASPEN can be inputted into ASPEN ； If it is the latter, it might be a bit more complicated; it is necessary to define the functional groups, determine what functional groups make up AB, and then use UNIFAC to estimate the interaction parameters.
Reply to 2# cl6119: It’s the latter. Once the interaction parameters between the groups are known, one of these groups is not present in Aspen and needs to be defined anew. How can a new functional group be defined? How are substances composed of this functional group configured?
There should be instructions on this in ASPEN’s documentation. I did it a few years ago; I can’t remember the exact process, only that I followed the instructions. Roughly, components and functional groups are defined within the components.